Fig. 5

Metformin inhibits growth of myeloma cells in an AMPK-dependent manner. a Western blot showing that metformin activates AMPK and upregulated TSC2 to inhibit mTOR in RPMI8226 and U266 cells. b CCK8 assay showing that the specific AMPK inhibitor compound C abrogated the metformin-induced RPMI8226 and U266 cells growth inhibition. c CCK8 assay showing that siRNA-mediated knockdown of AMPK in RPMI8226 and U266 cells attenuated metformin-induced cell growth inhibition. d Western blot analysis showing that siRNA-mediated knockdown of AMPK in RPMI8226 and U266 cells failed to inhibit phosphorylation of the mTORC1/C2 signaling pathways. *P < 0.05 and **P < 0.05 compared with the control group